Lynch syndrome and exposure to aristolochic acid in upper-tract urothelial carcinoma: its clinical impact?

Upper Tract Urothelial Carcinoma in the Lynch Syndrome Tumour Spectrum: A Comprehensive Overview from the European Association of Urology - Young Academic Urologists and the Global Society of Rare Genitourinary Tumors

CONTEXT

Upper tract urothelial carcinoma (UTUC) represents the third most frequent malignancy in Lynch syndrome (LS).

OBJECTIVE

To systematically review the available literature focused on incidence, diagnosis, clinicopathological features, oncological outcomes, and screening protocols for UTUC among LS patients.

EVIDENCE ACQUISITION

Medline, Scopus, Google Scholar, and Cochrane Database of Systematic Reviews were searched up to May 2021. Risk of bias was determined using the modified Cochrane tool. A narrative synthesis was undertaken.

EVIDENCE SYNTHESIS

Overall, 43 studies between 1996 and 2020 were included. LS patients exhibited a 14-fold increased risk of UTUC compared with the general population, which further increased to 75-fold among hMSH2 mutation carriers. Patients younger than 65 yr and patients with personal or family history of LS-related cancers should be referred to molecular testing on tumour specimen and subsequent genetic testing to confirm LS. Newly diagnosed LS patients may benefit from a multidisciplinary management team including gastroenterologist and gynaecologist specialists, while genetic counselling should be recommended to first-degree relatives (FDRs). Compared with sporadic UTUC individuals, LS patients were significantly younger (p = 0.005) and exhibited a prevalent ureteral location (p = 0.01). Radical nephroureterectomy was performed in 75% of patients (5-yr cancer-specific survival: 91%). No consensus on screening protocols for UTUC was achieved: starting age varied between 25-35 and 50 yr, while urinary cytology showed sensitivity of 29% and was not recommended for screening.

CONCLUSIONS

Urologists should recognise patients at high risk for LS and address them to a comprehensive diagnostic pathway, including molecular and genetic testing. Newly diagnosed LS patients should be referred to a multidisciplinary team, while genetic counselling should be recommended to FDRs.

PATIENT SUMMARY

In this systematic review, we analysed the existing literature focused on upper tract urothelial carcinoma (UTUC) among patients with Lynch syndrome (LS). Our purpose is to provide a comprehensive overview of LS-related UTUC to reduce misdiagnosis and improve patient prognosis.

Aristolochic Acid-Induced Genotoxicity and Toxicogenomic Changes in Rodents

Aristolochic acid (AA) is a group of structurally related nitrophenanthrene carboxylic acids found in many plants that are widely used by many cultures as traditional herbal medicines. AA is a causative agent for Chinese herbs nephropathy, a term replaced later by AA nephropathy. Evidence indicates that AA is nephrotoxic, genotoxic, and carcinogenic in humans; and it also induces tumors in the forestomach, kidney, renal pelvis, urinary bladder, and lung of rats and mice. Therefore, plants containing AA have been classified as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer. In our laboratories, we have conducted a series of genotoxicity and toxicogenomic studies in the rats exposed to AA of 0.1–10 mg/kg for 12 weeks. Our results demonstrated that AA treatments induced DNA adducts and mutations in the kidney, liver, and spleen of rats, as well as significant alteration of gene expression in both its target and nontarget tissues. AA treatments altered mutagenesis- or carcinogenesis-related microRNA expression in rat kidney and resulted in significant changes in protein expression profiling. We also applied benchmark dose (BMD) modeling to the 3-month AA-induced genotoxicity data. The obtained BMDL₁₀ (the lower 95% confidence interval of the BMD₁₀ that is a 10% increase over the background level) for AA-induced mutations in the kidney of rats was about 7 μg/kg body weight per day. This review constitutes an overview of our investigations on AA-induced genotoxicity and toxicogenomic changes including gene expression, microRNA expression, and proteomics; and presents updated information focused on AA-induced genotoxicity in rodents.